Spatial-temporal differentiation of mountain-water-forest-farmland-lake-grass system in Qinghai area of the Qilian Mountain National Park, China

Abstract

Higher and more precise requirements are critically needed for the protection, regulation, and restoration of ecological environment in the Qilian Mountain National Park after it is classified as a national park system pilot in China. Based on remote sensing data in 1980-2018, the spatial pattern map of mountain-water-forest-farmland-lake-grass system was constructed to analyze its spatial-temporal variations in the general control area and core conservation area in Qinghai area of the Qilian Mountain National Park. The results showed that grasslands, with an area of 8174.93 km2, were the main landscape in the park, and that grassland area in the core conservation area was 1.2 times as that of the general control area. The bare exposed rocks, a major type of unused land, accounted for 86.7% and 79.4% of the unused land in the core conservation area and the general control area, respectively. Forest area in the general control area was larger than that in the core conservation area. Water area in the core conservation area was 4.9 times as large as that in the general control area, with 90.4% of which being dominated by permanent glaciers and snowfields. The drylands were mainly concentrated in the general control area. From 1980 to 2018, the water area was decreasing and had been reduced by 186.75 km2. The area of permanent glaciers and snowfields decreased the most, with a drop of 12.05 and 175.88 km2 in the general control area and the core conservation area, respectively. The area of forests and grasslands were enlarged constantly. The changes of high-, medium-, and low-coverage grasslands in the core conservation area were greater than that in the general control area, which were the most significant during 1990-2000. Moreover, the degradation of high- and medium-coverage grasslands in the general control area as well as high- and low-coverage grasslands in the core conservation area was observed from 1980 to 2018. The area of bare exposed rocks was on the rise, while the permanent glaciers and snowfields displayed a decreasing trend. The permanent glaciers and snowfields and the bare exposed rocks exhibited the most obvious changes in the park. The glaciers in the core conservation area retreated remarkably faster than those in the general control area, which were transformed into the bare exposed rocks mainly in 1980-1990 and 2000-2010.